623
awareness, wetlands have been indiscriminately
and deliberately destroyed with a short-sighted
outlook for instant gains. For example, 60 % of
wetlands worldwide and up to 90 % in Europe
have been destroyed over the past century,
mainly due to agriculture, pollution, development of dams, canals, groundwater pumping,
urban development, peat extraction, etc. Further,
if a lake or a wetland is used as a reservoir, it
frequently results in a barren zone of bare earth
or mud around its shore. It is because water tends
to be drawn off at times where infl ow is low. This
‘drawdown’ kills the vegetation and its associated animals of the littoral zone.
29.2.1 Problems Faced by Wetlands
Burgeoning population, intensifi ed human activity, unplanned development, absence of management structure, lack of proper legislation and lack
of awareness about the vital role played by these
ecosystems (functions, values, etc.) are the important causes that have contributed to their decline
and extinction. With these, wetlands are permanently destroyed and lose any potential for rehabilitation. This has been leading to ecological
disasters in some areas, in the form of large- scale
devastations due to fl oods, etc. According to one
estimate, c 50 % of the world’s wetlands have
already been lost.
29.2.2 Problems of Physico-chemical
Nature
The problems of physico-chemical nature include
the aspects like siltation and shrinkage.
29.2.2.1 Problems with Regard
to Siltation and Shrinkage
As a typical example, study showed that within a
span of 100 years (approx) from 1880 to 1980,
there was shrinkage of c 3,539.6 ha of the water
spread area (Fig. 29.1 ) of Sone Beel (Kar 2012 ).
This is the fate of other wetlands as well.
Extensive deforestation coupled with soil erosion
had been leading to large-scale siltation of the
water bodies, thus causing shrinkage in the water
spread area. One can expect further diminution in
the water spread area due to the siltation process,
if it continues (Kar 2007 ).
29.2.2.2 Problems with Regard
to Pollution
The degradation of water quality is a direct
consequence of population growth, urbanisation
and industrialisation. Unrestricted dumping of
sewage with toxic chemicals has polluted many
freshwater wetlands, making them unfi t for
drinking, fi shing or bathing in most parts of India.
According to the study conducted by Chopra
( 1985 ), more than 50,000 small and large lakes in
India are polluted to the point of being considered
‘dead’. The natural coastal wetlands are also
polluted to the extent that their fi shery and
recreational values are lost. The prime sources of
pollution are domestic and industrial sewage as
point source besides agricultural run-off and the
more insidious atmospheric pollution contributing to the non-point source pollution. Studies
suggest that 70 % of the 3,100 cities and towns
(with population >100,000 each) in India have no
sewage treatment facilities.
29.2.2.3 Global Climate Change Effects
Wetlands both contribute to and suffer from climate change. They are the single largest source
of methane, a gas that is a major contributor to
the atmospheric trapping of heat which leads to
global warming. Unlike most regions of the
world, the population of India has been high
enough to cause changes in the landscape.
Continued degradation of water and wetland
resources means that extensive regions will be
marginalised or rendered less habitable by people and domestic animals if a warming and drying cycle of change affects India’s climate.
Notwithstanding the above, there have been
some works on the role of wetlands in global climate change (Immirzi et al. 1992 ; Mitsch and Wu
1995 ; and so on).
29.2 Problems
awareness, wetlands have been indiscriminately
and deliberately destroyed with a short-sighted
outlook for instant gains. For example, 60 % of
wetlands worldwide and up to 90 % in Europe
have been destroyed over the past century,
mainly due to agriculture, pollution, development of dams, canals, groundwater pumping,
urban development, peat extraction, etc. Further,
if a lake or a wetland is used as a reservoir, it
frequently results in a barren zone of bare earth
or mud around its shore. It is because water tends
to be drawn off at times where infl ow is low. This
‘drawdown’ kills the vegetation and its associated animals of the littoral zone.
29.2.1 Problems Faced by Wetlands
Burgeoning population, intensifi ed human activity, unplanned development, absence of management structure, lack of proper legislation and lack
of awareness about the vital role played by these
ecosystems (functions, values, etc.) are the important causes that have contributed to their decline
and extinction. With these, wetlands are permanently destroyed and lose any potential for rehabilitation. This has been leading to ecological
disasters in some areas, in the form of large- scale
devastations due to fl oods, etc. According to one
estimate, c 50 % of the world’s wetlands have
already been lost.
29.2.2 Problems of Physico-chemical
Nature
The problems of physico-chemical nature include
the aspects like siltation and shrinkage.
29.2.2.1 Problems with Regard
to Siltation and Shrinkage
As a typical example, study showed that within a
span of 100 years (approx) from 1880 to 1980,
there was shrinkage of c 3,539.6 ha of the water
spread area (Fig. 29.1 ) of Sone Beel (Kar 2012 ).
This is the fate of other wetlands as well.
Extensive deforestation coupled with soil erosion
had been leading to large-scale siltation of the
water bodies, thus causing shrinkage in the water
spread area. One can expect further diminution in
the water spread area due to the siltation process,
if it continues (Kar 2007 ).
29.2.2.2 Problems with Regard
to Pollution
The degradation of water quality is a direct
consequence of population growth, urbanisation
and industrialisation. Unrestricted dumping of
sewage with toxic chemicals has polluted many
freshwater wetlands, making them unfi t for
drinking, fi shing or bathing in most parts of India.
According to the study conducted by Chopra
( 1985 ), more than 50,000 small and large lakes in
India are polluted to the point of being considered
‘dead’. The natural coastal wetlands are also
polluted to the extent that their fi shery and
recreational values are lost. The prime sources of
pollution are domestic and industrial sewage as
point source besides agricultural run-off and the
more insidious atmospheric pollution contributing to the non-point source pollution. Studies
suggest that 70 % of the 3,100 cities and towns
(with population >100,000 each) in India have no
sewage treatment facilities.
29.2.2.3 Global Climate Change Effects
Wetlands both contribute to and suffer from climate change. They are the single largest source
of methane, a gas that is a major contributor to
the atmospheric trapping of heat which leads to
global warming. Unlike most regions of the
world, the population of India has been high
enough to cause changes in the landscape.
Continued degradation of water and wetland
resources means that extensive regions will be
marginalised or rendered less habitable by people and domestic animals if a warming and drying cycle of change affects India’s climate.
Notwithstanding the above, there have been
some works on the role of wetlands in global climate change (Immirzi et al. 1992 ; Mitsch and Wu
1995 ; and so on).
29.2 Problems